Display apparatus and method for automotive vehicle

ABSTRACT

In display apparatus and method for an automotive vehicle in which an image display is mounted, a road map data image is stored in a storage medium, a mark representing the present position of the vehicle is superimposed on the road map data image, the road map data image is rotated on an image screen of the image display in accordance with a traveling direction of the vehicle while displaying the road map data image on an image screen of the image display, and a display form of the displayed road map data image is varied between a region of the road map data image which is near to a displayed position at which the vehicle is present and another region thereof which is remote from the displayed position thereof while rotating the road map data image on the image screen of the image display section.

TECHNICAL FIELD

The present invention relates to display apparatus and method for anautomotive vehicle such as, so-called, car navigation system and method.The present invention, more particularly, relates to a technique forimproving a visibility of an image displayed on an image screen of adisplay.

BACKGROUND ART

A Japanese Patent Application First Publication No. Heisei 10-148534published on Jun. 2, 1998 exemplifies a previously proposed vehiculardisplay apparatus. In the previously proposed vehicular displayapparatus disclosed in the above-identified Japanese Patent ApplicationFirst Publication, in a case where a vehicular steering wheel is steeredtoward a center of the vehicle in order to turn the vehicle, the imagescreen of the display is switched to a state in which a visibility ofthe whole image screen of the display is lowered so that a vehiculardriver does not feel troublesome.

DISCLOSURE OF THE INVENTION

However, since, in the previously proposed vehicular display apparatusdisclosed in the above-identified Japanese Patent Application FirstPublication, the visibility of the whole display image screen ismodified, there is a possibility that the vehicular driver still feelstroublesome.

It is, therefore, an object of the present invention to provide displayapparatus and method for an automotive vehicle which meet a vehiculardriving sense of the vehicular driver while improving a visibility ofthe displayed image.

According to one aspect of the present invention, there is provided adisplay apparatus for an automotive vehicle, comprising: an imagedisplay section; a present position measuring section that measures apresent position of the vehicle; a road map storing section that storesa road map data image; a superimpose processing section thatsuperimposes a mark representing the present position of the vehicle onthe road map data image to display the road map data image on which themark is superimposed through the image display section; and displaycontrol section that rotates the road map data image displayed on animage screen of the image display section in accordance with a travelingdirection of the vehicle and varies a display form of the displayed roadmap data image between a region of the road map data image which is nearto a displayed position at which the vehicle is present and anotherregion of the road map data image which is remote from the displayedposition thereof when rotating the road map data image on the imagescreen displayed on the image display section.

This disclosure of the invention does not necessarily describe allnecessary features so that the invention may also be a sub-combinationof these described features.

BRIEF DESCRIPTION OF THE DRAWINGS

The file of this patent contains at least one drawing executed in color.Copies of this patent or patent application publication with colordrawing(s) will be provided by the Patent and Trademark Office uponrequest and payment of the necessary fee.

FIG. 1 is a block diagram representing a structure of a vehiculardisplay apparatus according to the present invention related to each offirst, second, third, fourth, fifth, and sixth preferred embodiments.

FIG. 2 is a block diagram representing a more detailed structure ofvehicular display apparatus related to the first, third, and fourthpreferred embodiments.

FIG. 3 is a processing flowchart representing a procedure of thevehicular display apparatus in the first preferred embodiment.

FIGS. 4A and 4B are characteristic curves on an image contrast preset ina display form setting table, respectively.

FIG. 5 is a photograph representing a display example of a displayedimage on a display when the vehicle has traveled in a straight run.

FIG. 6 is a photograph representing a display example of a displayedimage on display when a contrast of road map data image is changedduring a rotation of road map.

FIG. 7 is a photograph of a display example of a road map data imagewhen a brightness of the road map data image is varied during therotation of road map data image.

FIG. 8A is a photograph of a display example of the road map data imagewhen a focus of the road map data image is varied during the rotation ofroad map data image.

FIG. 8B is a photograph of a display example of the road map data imagewhen a contrast of a region of the road map data image which surroundsan arrowed mark representing a present position of the vehicle is raisedand that of another region of the road map data which is remote from thedisplayed arrowed mark is lowered.

FIG. 8C is a photograph representing a display example of the displayedimage when a saturation of a region of the road map data image whichsurrounds the arrowed mark is lowered as compared with another regionthereof which is remote from the arrowed mark.

FIG. 9 is a photograph representing an example of the roadmap data imagein a form of a bird Is eye view displayed on the display to which thepresent invention is applicable.

FIG. 10 is a photograph representing an example of the displayed roadmap data image in the form of the bird's eye view to which a contrastprocess described in the first embodiment shown in FIGS. 1 and 2 isadded.

FIG. 11 is a detailed block diagram of the vehicular display apparatusin the second preferred embodiment according to the present invention.

FIG. 12 is a characteristic graph representing an example of varying thedisplay form according to a circumferential velocity V1 and a luminanceof an area surrounding the vehicle used in the second embodiment shownin FIG. 11.

FIG. 13 is an operational flowchart representing a procedure ofvehicular display apparatus in the third preferred embodiment accordingto the present invention.

FIG. 14 is a photograph of a display example of display representing aroad map data image processed in a simplification process carried out inthe third embodiment shown in FIGS. 1 and 13.

FIG. 15 is an operational flowchart representing a procedure ofvehicular display apparatus in the fourth preferred embodiment accordingto the present invention.

FIG. 16 is a photograph representing a display example of the displayedimage of display when a ratio of a road map data image before a rotationof the road map data image to that after the rotation thereof is 10:0.

FIG. 17 is a photograph representing a display example of the displayedimage of display when the ratio of the road map data image before therotation of the road map data image to that after the rotation thereofis 7:3.

FIG. 18 is a photograph representing a display example of the displayedimage of display when the ratio of road map data image before therotation of the road map data image to that after the rotation thereofis 5:5.

FIG. 19 a photograph representing a display example of the displayedimage of display when the ratio of road map data image before therotation of the road map data image to that after the rotation thereofis 3:7.

FIG. 20 is a photograph representing a display example of the displayedimage of display when the ratio of road map data image before therotation of the road map data image to that after the rotation thereofis 0:10.

FIG. 21 is an operational flowchart representing a procedure carried outin the vehicular display apparatus in the fifth preferred embodimentaccording to the present invention.

FIG. 22 is a block diagram of the structure of the vehicular displayapparatus in the sixth preferred embodiment according to the presentinvention.

FIGS. 23, 24, and 25 are integrally a procedure flowchart executed inthe vehicular display apparatus of the sixth preferred embodiment shownin FIGS. 1 and 22.

FIG. 26A is a timing chart representing start and end of a turning ofthe vehicle.

FIGS. 26B, 26C, and 26D are timing charts representing start and end ofthe rotation of each display form varied road map data image.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will hereinafter be made to the drawings in order tofacilitate a better understanding of the present invention

FIG. 1 shows a whole configuration of a display apparatus for anautomotive vehicle (hereinafter, also referred to as a vehicular displayapparatus) related to each preferred embodiment according to the presentinvention. As shown in FIG. 1, vehicular display apparatus 1 includes: apresent position measuring unit 2 which measures a present position ofthe vehicle (hereinafter, also referred to as a host vehicle); a GPS(Global Positioning System) antenna 2 which receives GPS signalsradiated from a plurality of position measuring satellites; a gyrosensor 4 which measures a traveling direction of the host vehicle; adistance measurement sensor 5 which measures a running distance of thevehicle; a display (corresponding to image display means) 7; and adisplay controller 6 which controls an image display onto display 7.

Present position measuring unit 2 measures an absolute position of thehost vehicle on the basis of a position measurement information receivedfrom GPS antenna 3. In addition, in a case where the GPS signals cannotbe received, the present position of the vehicle is measured using aself-contained navigation (SCN) method based on the position measurementdata obtained from gyro sensor 4 and distance sensor 5. It is noted thatdisplay 7 may be constituted by a liquid crystal display, presentposition measuring unit 2 and display controller 7 may be constituted bya microcomputer and its peripheral circuit.

FIG. 2 shows a functional block diagram representing a structure of thevehicular display apparatus 1 related to each of first, second, third,fourth, and fifth preferred embodiments according to the presentinvention. As shown in FIG. 2, display controller (corresponding todisplay control means) 6 includes a velocity calculating section 11; an(arithmetically) comparing section 12; a display form adjusting section13; and a display image data generating section 14. In addition, displaycontroller 6 includes a display form setting table which stores settingdata needed when the display form adjusting section 13 adjusts thedisplay form; and a road map data storing section 22 which stores a roadmap data image placed in a proximity to a running position of the hostvehicle.

Velocity calculating section 11 detects a circumferential velocity V1 atvarious points of places (given spots) on the road map data imagedisplayed on display 7 along with a turn of the vehicle when thevehicular driver steers a vehicular steering wheel to turn the vehicleso that a traveling direction of the vehicle measured by presentposition measuring section 2 is changed. In addition, velocitycalculating section 11 has a function to calculate a turning angle θ1 ofthe vehicle within a predetermined period of time when the travelingdirection of the vehicle is changed, as will be described later in eachof the third and fourth preferred embodiments.

In comparing section 12, a reference value Vref of the circumferentialvelocity is preset. Comparing section 12 compares the circumferentialvelocity V1 derived by velocity calculating section 11 with referencevalue Vref to determine whether the circumferential velocity V1 islarger than reference value Vref thereof. A signal indicating a resultof the determination described above is supplied to display formadjusting section 13. In addition, another reference value θref of aturning angle of the vehicle with another predetermined period of timeis preset in comparing section 12 as will be described later in each ofthe third and fourth preferred embodiments according to the presentinvention. Then, comparing section 12 compares the turning angle θ1derived by velocity calculating section 11 with reference value θref.

Display form adjusting section 13 carries out a proper modification(variation) of a display form of the road map data image displayed ondisplay 7 when comparing section 12 determines that the circumferentialvelocity V1 of the image on display 7 is larger than a reference valueVref of circumferential velocity described above. The display formincludes an image contrast, an image brightness, an image saturation,and a simplification (simplifying process) of the displayed image.Display form adjusting section 13 adjusts at least one of display formsof these items on the basis of data stored in display form setting table21 in such a procedure as will be described later.

Furthermore, display form adjusting section 13 has a function toimplement a display process such as to superimpose a road map data imageafter the traveling direction of the vehicle is changed on that beforethe traveling direction of the vehicle is changed.

Display image data generating section 14 carries out a process ofgenerating an image to be displayed on display 7 on the basis of roadmap data read from road map storing section 22, data on the presentposition of the vehicle and the traveling direction of the vehiclesupplied from present position measuring unit 2, and data on variouskinds of display forms supplied from display form adjusting section 13.It is noted that road map data storing section 22 may be constituted byan external storage medium and driver therefor.

Next, an operation of the first preferred embodiment of vehiculardisplay apparatus 1 will be described with reference to a flowchartshown in FIG. 3.

At a step ST1, present position measuring section 2 measures the presentposition of the host vehicle on the basis of data obtained by GPSantenna 3 or by both of distance sensor 5 and gyro sensor 4. At the nextstep ST2, display image data generating section 14 reads road map dataof a surrounding regional area with a point of place at which thevehicle is running as a center from road map data storing section 22. Atthe next step ST3, display image data generating section 14 superimposesa mark representing the position of the host vehicle on the road mapdata image. At the next step ST4, display image data generating section14 generates the image data to be displayed on display 7.

Next, if the vehicular driver steers a steering wheel of the vehicle tochange the traveling direction of the vehicle (Yes at a step ST5),display image data generating section 14 rotates the road map data imagewith the position of the vehicle to be displayed as a center so as toadjust the traveling direction of the vehicle on display 7 to usuallyindicate the same direction as the actual traveling direction thereof.At the same time, velocity calculating section 11 calculates rotationvelocity at various point of places (various given points) on the roadmap data image along with the steering operation, namely,circumferential velocities V1. It is noted that circumferentialvelocities V1 can easily be derived on the basis of a rotation velocityof the road map image data and respective distances of the respectivepoints of places to the center of the image (viz., the position of thevehicle).

At a step ST6, comparing section 12 compares the preset reference valueVref of circumferential velocity (Vref is, for example, 50 mm/s(millimeter/second)) with each of circumferential velocities V1calculated by velocity calculating section 11 to determine whether aposition (a point of place) on the road map data image at whichcorresponding magnitude of circumferential velocity V1 becomes largerthan reference value Vref is present on the image screen of display 7.If Yes at step ST6, namely, the above-described position on the road mapdata image is determined to be present, display form adjusting section13 then carries out such a process as to adjust the image contrast alongwith the rotation of road map data image on the image screen of display7 at the next step ST7. It is noted that although an adjustment on thecontrast, as one example, will herein be explained, the adjustment ofbrightness, saturation, focus, or a combination of these elements ispossible.

The adjustment process of the contrast is set in accordance with acharacteristic graph stored in display form setting table 21. FIG. 4Ashows the characteristic graph representing a relationship betweencircumferential velocity V1 and contrast. As shown in FIG. 4A, at theposition at which the corresponding magnitude of circumferentialvelocity V1 which is equal to or lower than 50 mm/s, a high contrast(the same contrast as that in an ordinary display) is maintained. Such aprocessing as reducing the contrast in the form of a first-orderfunction with respect to an increase in circumferential velocity V1 whencircumferential velocity V1 falls in a range between 50 mm/s and 150mm/s is added. Furthermore, if circumferential velocity V1 is in excessof 150 mm/s, such a process as to reduce further the contrast is notcarried out.

Then, the image to which the adjustment process of the contrast is addedis displayed on the image screen of display 7 (at a step ST8 in FIG. 3).Thereafter, the above-described series of processes of steps ST1 throughST8 are repeated until an ignition switch of the host vehicle is turnedoff (Yes at a step ST9).

FIG. 5 shows a display example of display 7 when the vehicle (thepresent position (including the traveling direction) is represented byan arrowed mark in red) is running ordinarily (or normally).

FIG. 6 shows a display example of the image screen of display 7 when thecontrast of the road map data image displayed through display 7 isvaried when the traveling direction of the host vehicle is changed.

As appreciated from FIGS. 5 and 6, the road map data image displayed onthe image screen of display 7 is adjusted in such a manner that, as theroad map data image becomes apart from the displayed position of thevehicle (represented by the arrowed mark), the contrast thereon becomesgenerally lowered. Hence, when the traveling direction of the vehicle ischanged at, for example, a traffic intersection, a vehicular occupant(including vehicular driver) can avoid a troublesomeness caused by therotation of the road map data image on the image screen of display 7 sothat the visibility of road map data image can be improved.

In the first embodiment, the example of setting the relationship betweencircumferential velocity V1 and contrast of road map data image usingthe characteristic graph as shown in FIG. 4A has been explained.However, the present invention is not limited to this. That is to say,as shown in a characteristic graph of FIG. 4B, it is also possible toreduce the contrast in the form of the first-order function as a regionof the road map data image becomes remote from the rotation center ofthe road map data image. In this case, such a comparison process ascomparing circumferential velocity V1 with reference value Vref ofcircumferential velocity in the comparing section 12 can be omitted.

In addition, in the first embodiment, circumferential velocity V1 oneach of various points of places is derived and the display form such asthe contrast is changed on the basis of a magnitude of circumferentialvelocity V1. However, the present invention is not limited to this. Itis possible to vary the display form on the basis of an angular velocityAV of each of the various points of places, each distance D of thevarious points of places from the rotation center, and a magnitude of avisual sense variation rate R. In this case, each lateral axis in thecharacteristic graphs of FIGS. 4A and 4B denotes any one of angularvelocity AV, distance D from the rotation center, visual sense variationrate R.

In addition, in the first embodiment, display form adjusting section 13adjusts the contrast on the road map data image. However, as anotherdisplay form, the brightness, the saturation, and focus of the road mapdata image may be adjusted.

FIG. 7 shows a display example of the image screen of display 7 when thebrightness of road map data image is adjusted. As shown in FIG. 7, withthe present position of the vehicle on the image screen of display 7 asthe center, as the region of the road map image becomes more remote fromthe present position of the vehicle on the image screen, the brightnessof the road map data image becomes lowered. Even in such a display formas shown in FIG. 7, the troublesome feeling that the vehicular occupantgives when the road map data image is rotated can be avoided in the samemanner as described above.

Furthermore, FIG. 8A shows a display example of adjusting the focus ofthe road map data image by display form adjusting section 13 in such amanner that an adjacent portion of the rotation center on the road mapdata image is clearly displayed and, as the region of the road map dataimage becomes more remote from the rotation center, the image becomesshaded. In the case of the display form of adjusting the focus, thetroublesome feeling that the vehicular occupant gives during therotation of the road map data image can be avoided and the visibility ofthe image screen of display 7 can be improved.

It is noted that FIG. 8B shows a display example on the display imagescreen of display 7 in which the contrast of a region of the road mapdata image which is near to the present position of the vehicleindicated by the arrowed mark is lowered and that of another regionthereof which is remote from the center of rotation (arrowed markposition) is raised and FIG. 8C shows a display example on the displayimage screen of display 7 in which the saturation of the remote regionfrom the position of the arrowed mark is lowered than that of the regionnear to the arrowed mark position.

In addition, it is possible not only to vary various display formsconcentrically (contrast, brightness, saturation, focus, and so forth)with the present position of the vehicle on the road map data image asthe center but also to adjust the display form at a desired portion onthe road map data image in such a manner as only an upper portion of thedisplay image screen of display 7 or only a lower portion thereof.

In the first preferred embodiment described above, such a series ofprocesses as for a plan view road map data image displayed on the imagescreen of display 7 has been explained. However, the same series ofprocesses described above are applicable to the road map data image in aform of a bird's eye view (perspective view).

FIG. 9 shows a display example of the bird's eye view displayed on theimage screen of display 7. As shown in FIG. 9, the region of the roadmap data image in the form of the bird's eye view which is near to thepresent position of the vehicle indicated by the arrowed mark isdisplayed approximately three-dimensionally. Then, when the travelingdirection of the vehicle is changed and the road map data image in theform of the bird's eye view is rotated, the contrast of the region whichis remote from the arrowed mark position (the present position of thehost vehicle) is lowered, as shown in FIG. 10. Hence, even in the bird'seye view formed road map data image, the troublesome feeling that thevehicular occupant gives during the rotation of the road map data imagecan be reduced.

Next, the second preferred embodiment of vehicular display apparatus 1will be described below.

FIG. 11 shows a block diagram representing the structure of vehiculardisplay apparatus 1 in the second preferred embodiment according to thepresent invention.

As shown in FIG. 11, an addition of a luminance sensor 23 is a point ofdifference from vehicular display apparatus 1 in the case of the firstembodiment shown in FIG. 2.

Luminance sensor 23 is a sensor to detect a luminance of a surroundingarea of the vehicle. In this embodiment, the display form of the roadmap image data on display 7 is adjusted on the basis of detected data ofthe luminance sensor 23.

In addition, FIG. 12 shows characteristic graphs representing eachrelationship between circumferential velocity V1 of the rotating roadmapdata image and a luminance (it is noted that the contrast, thesaturation, or focus may be adopted in place of the luminance) of theroad map data image displayed on display 7 and which are set in displayform setting table 21. Characteristic graphs representing therelationship between the luminance and circumferential velocity V1 aredifferent between that in the case where the surrounding area of thevehicle is bright and that in the case where the surrounding area of thevehicle is dark.

That is to say, when the luminance of the surrounding area of thevehicle is determined to be equal to or larger than a predeterminedlevel, the brightness is set to be varied gradually like the first-orderfunction in the range of circumferential velocity V1 from 50 to 150 mm/sas shown by a characteristic curve of S1 in FIG. 12. When the luminanceof the surrounding area of the vehicle is lower than the predeterminedlevel, the brightness is set to be varied abruptly like the first-orderfunction in the range of circumferential velocity V1 from 50 to 100mm/s, as shown by another characteristic curve of S2 in FIG. 12.

In the second embodiment described above, in such a case where theluminance of the surrounding area of the vehicle is low as a night time,rainy weather, or run in a tunnel at which the vehicular occupant isparticularly easy to feel troublesome, a rate of variation in thebrightness with respect to circumferential velocity V1 is set to belarge. Hence, the troublesome feeling can be reduced and the visibilityof display 7 can be improved. In addition, in such a case where theluminance of the surrounding area is bright as a daytime, the brightnessis set to be varied moderately with respect to circumferential velocityV1 so that a required information can accurately be recognized.

Next, the third preferred embodiment of vehicular display apparatus 1according to the present invention will be described below.

In the third embodiment, the road map data image becomes simplified anddisplayed as the region of the road map data image becomes more remotefrom the center of rotation along with the rotation of the road map dataimage on the image screen of display 7 so that the troublesome feelingthat the vehicular occupant gives can be reduced. The structure of thethird embodiment is the same as the block diagram shown in FIG. 2 of thefirst embodiment described above.

The operation of vehicular display apparatus 1 in the third embodimentwill be explained with reference to the block diagram shown in FIG. 2and an operational flowchart shown in FIG. 13.

First, at a step ST11, present position measuring unit 2 detects a runposition of the vehicle. Then, at a step ST12, display controller 6determines whether the ignition switch is turned off. If No at stepST12, the routine goes to a step ST13. At step ST13, display image datagenerating section 14 of display controller 6 carries out such a processas to superimpose and display the present position of the vehicle (thearrowed mark) on the region of the road map data stored in road map datastoring section 22 which surrounds the point of place at which thevehicle is running.

Next, at a step ST14, velocity calculating section 11 carries out such aprocess as to derive a turning angle θ1 of the vehicle within apredetermined period of time on the basis of data on the presentposition of the vehicle obtained by present position measuring unit 2.Then, at a step ST15, comparing section 12 compares the turning angle θ1with the preset reference value θref in the comparing section 12 todetermine whether θ1>θref. If θ1>θref (Yes) at step ST15, the routinegoes to a step ST16. If θ1≦θref (No), the routine jumps to step ST12. Atstep ST16, display form adjusting section 13 carries out such a processas to simplify the road map data image for the region of the road mapdata image which is equal to or longer than a predetermined distancevalue from the center of rotation and to display the other region of theroad map data image which is shorter than the predetermined distancevalue from the rotation center normally without the simplificationprocess. Then, at the next step ST17, the generated image data isdisplayed on the image screen of display 7.

FIG. 14 shows a display example representing an example of the road mapdata image which has been processed under the simplification process asdescribed in the third embodiment.

As appreciated from FIG. 14, for the region of the road map data imagewhich surrounds the displayed present position of the vehicle (arrowedmark, viz., which provides the center of rotation on the road map dataimage), the road map data image is displayed normally in details and forthe other region of the road map data image which is remote from thecenter of rotation by the predetermined distance value, the road mapdata image is simplified and displayed. The meaning of this term ofsimplified is that the detailed road map information is omitted. Hence,the troublesome feeling that the vehicular occupant gives when the roadmap data image is rotated can be reduced and the visibility of the imagescreen on display 7 can be improved.

Next, the fourth preferred embodiment of vehicular display apparatus 1will be described below.

In the fourth embodiment, along with the rotation of the road map dataimage on the image screen of display 7, the image before the rotationand that after the rotation are superimposed together and displayed anda ratio of this superimposition is varied gradually so that the road mapdata image on display 7 is rotated without giving the vehicular occupantthe troublesome feeling. The structure of vehicular display apparatus 1in the fourth embodiment is the same as the block diagram of FIG. 2.

FIG. 15 shows a processing flowchart of the fourth preferred embodimentfor explaining the operation of vehicular display apparatus 1 in thefourth embodiment.

At a step ST21, present position measuring unit 2 detects the runningposition of the vehicle (it is natural that the traveling directionthereof is measured). At a step ST22, display controller 6 receives theignition switch position information to determine whether the ignitionswitch is turned off. If the ignition switch is not turned off (No) atstep ST22, the routine goes to a step ST22. If the ignition switch isturned off (Yes) at step ST22, the routine is ended. At step ST23,display image data generating section 14 of display controller 6 carriesout such a process as to superimpose the present position of the vehicle(arrowed mark) on the region of the road map data which surrounds therunning point of place of the vehicle stored in road map data storingsection 22 and displays the arrowed mark superimposed road map dataimage on the image screen of display 7.

Then, at the next step ST24,velocity calculating section 11 derives therotation angle θ1 of the vehicle within the predetermined period of timeon the basis of the data on the present position of the vehicle obtainedby present position measuring unit 2. Then, the routine goes to a stepST24. At step ST24, comparing section 12 compares reference value θrefpreset in calculating section 12 with rotation angle θ1 of the vehicleto determine whether θ1>θref. If θ1>θref (Yes) at step ST25, the routinegoes to a step ST26. At step ST26, display form adjusting section 13carries out such a process as to turn a count value of L indicating alevel of an image processing to 0 (L=0). Then, the image of level L isdisplayed on image screen of level L at the next step ST27.

It is noted that level L is a level indicating a magnitude of thesuperimposition of two images, when L=0, the image to be displayed isthe whole road map data image before the traveling direction of thevehicle is changed, and, when L=L1, the image to be displayed is thewhole road map data image after the traveling direction of the vehicleis changed. Suppose now that L1=5. In this case, when L=0, ansuperimposition ratio of the road map data image before the travelingdirection of the vehicle is changed to that after the travelingdirection thereof is changed is 10:0. When L=1, the same ratio indicates7:3. When L=2, the same ratio indicates 5:5. When L=3, the same ratioindicates 3:7. When L=4, the same ratio indicates 0:10.

Next, at a step ST27, display form adjusting section 13 of displaycontroller 6 carries out such a process as to generate the image oflevel L (at this time, L=0). Then, at the next step ST28, the generatedroad map data image on the image screen of display 7. Thereafter, thevalue of L is incremented by one (L=L+1) at a step ST29. Theabove-described process from step ST27 to step ST29 is repeated untilL=L1 at a step ST30. If L=L1 (in this case, L1=5) at step ST30 (Yes),the routine jumps to step ST24 and the same series of processes of stepsST24 to ST30 are repeated if θ1>θref at step ST25.

FIGS. 16, 17, 18, 19, and 20 show series of display examples of theimage screen of display 7 for explaining a variation pattern of the roadmap data image in the case of the display form adjustment carried out inthe fourth embodiment described above. In details, FIG. 16 shows theresult of image processing when L=0 (viz., the superimposition ratio ofthe road map data image before the rotation thereof to that after therotation thereof is 10:0). FIG. 17 shows the result of image processingwhen L=1 (the ratio thereof is 7:3). FIG. 18 shows the result of imageprocessing when L=2 (the same ratio is 5:5). FIG. 19 shows the result ofimage processing when L=3 (the same ratio is 3:7). FIG. 20 shows theresult of processing when L=4 (the same ratio is 0:10).

As appreciated from FIGS. 16 through 20, the image is displayed ondisplay 7 in such a manner that the superimposition ratio between twoimages (image before the rotation thereof and that after the rotationthereof) is gradually varied while the turn of the vehicle is startedand, then, the turn of the vehicle is ended.

As described above, in the fourth embodiment of vehicular displayapparatus 1 according to the present invention, when the travelingdirection of the vehicle is changed, the superimposition between theroad map data image before and after this direction change is carriedout and the superimposition ratio is set to be gradually varied.Therefore, the vehicular occupant can visually recognize the road mapdata image displayed on display 7 with a pleasant feeling. Consequently,the troublesome feeling that the vehicular occupant gives can berelieved.

Next, the fifth preferred embodiment of vehicular display apparatus 1will be described below.

In the fifth embodiment, such a process as to rotate the road map dataimage is carried out in such a manner as to synchronize the rotation ofthe road map data image displayed on the image screen of display 7 witha variation of a field of view for a vehicular forward zone of thevehicle that the vehicular occupant visually recognizes.

Hence, the road map data image can be displayed without giving anunpleasant feeling to the vehicular occupant. The structure of vehiculardisplay apparatus 1 in the fifth embodiment has the same structure asthe block diagram of FIG. 1 described above.

FIG. 21 shows a processing flowchart carried out in the fifthembodiment.

The operation of the fifth embodiment will be described with referenceto FIG. 21.

In FIG. 21, display controller 6 determines whether the ignition switchof the vehicle is turned off at a step ST31. At a step ST32, the presentposition measuring unit 2 measures the present position of the vehicleand traveling direction thereof.

At a step ST33, display controller 6 superimposes the arrowed markrepresenting the present position of the vehicle and direction thereofon the region of the road map data image which surrounds the runningposition of the vehicle and generates the image synthesized withcharacter data representing a name of place or so forth. Then, at thenext step ST34, the display controller 6 carries out such a process asto display the generated image on display 7.

Next, at a step ST35, display controller 6 carries out such a process asto calculate the traveling direction (vehicular direction) of thevehicle on the basis of the data on the traveling direction of thevehicle obtained by gyro sensor 4. At a step ST36, display controller 6determines whether a magnitude of the turning angle Δθ of the vehiclefor a predetermined period of time is larger (wider) than referencevalue θref preset in calculating section 12. If |Δθ|>θref (Yes) at stepST36, the routine goes to a step ST37. At step ST37, display controller6 carries out such a process as to rotate the road map data imagedisplayed on display 7 by the angle of Δθ in a reverse direction to theturning direction of the vehicle.

At this time, since the turning angle is measured on the basis of thedata derived by gyro sensor 4, the display image onto display 7 can begenerated at an earlier timing than such as a process as to read a newroad map data image and as to synthesize the characters. Hence, the roadmap data image can be rotated in synchronization with the turn of thevehicle.

Then, the image treated under the image processing is added with theprocess of varying appropriately the image contrast, brightness,saturation, and focus during the rotation of the road map data imageand, thereafter, the image processed road map data image is displayed onthe image screen of display 7 at steps ST38 and ST39.

As described above, in the fifth embodiment, when the travelingdirection of the vehicle is changed, the rotation of the road map dataimage to be displayed on display 7 is synchronized with the field ofview for the actual vehicular forward zone that the vehicular occupantvisually recognizes. The vehicular occupant can visually recognize theroad map data image displayed on display 7 without giving the unpleasantfeeling.

Next, the sixth preferred embodiment of vehicular display apparatus 1according to the present invention will be described below.

In the sixth embodiment, it is possible to adjust the rotation of theroad map data image to be displayed on display 7 on the basis of apredicted data derived according to a result of such a prediction as atraveling route of the vehicle.

FIG. 22 shows a block diagram representing the structure of vehiculardisplay apparatus in the sixth preferred embodiment.

As appreciated from FIG. 22, vehicular velocity display apparatus 1includes: present position measuring unit 2, GPS antenna 3, gyro sensor4, distance sensor 5, display controller 6, and display 7 in the sameway as the vehicular display apparatus shown in FIG. 1. In the sixthembodiment, a winker sensor 31 to detect a drive state of an winker ofthe vehicle and a vehicular velocity sensor 32 to detect a velocity ofthe vehicle.

The operation of vehicular display apparatus 1 in the sixth preferredembodiment will be described with reference to a series of operationalflowcharts shown in FIGS. 23 through 25.

Present position measuring unit 2 shown in FIG. 22 measures the positionof the vehicle on the basis of data obtained from the measuringsatellites through GPS antenna 3 and the data of the traveling directionand running distance of the vehicle obtained from gyro sensor 4 anddistance sensor 5.

Next, when the vehicular driver inputs a destination to which thevehicle is to be reached on display controller 6 at a step ST52. At astep ST53, display controller 6 carries out such a process as tocalculate a guide route to guide the vehicle from the present positionto the destination.

Then, the image display processing is carried out with a count value Nset as N=0 at a step ST54, the count value N representing a level of theimage processing. Then, at a step ST55, the image processing of level ofN=0 is carried out and the image processed road map data image isdisplayed. It is noted that the display image, at this time, is M0.

Next, a timer (not shown) provided within display controller 6 is resetat a step ST56. The present time T is set as T=0. Display controller 6determines whether the winker of the vehicle is presently operated at astep ST57 from a signal of winker sensor 31. If the winker is beingoperated (Yes at step ST57), the routine goes to a step ST58. At stepST58, display controller 6 determines whether a traffic intersection ispresent in the traveling direction of the vehicle on the basis of dataon the guide route. If the traffic intersection is present (Yes at stepST58), the routine goes to a step ST59. Display controller 6 carries outsuch a process as to estimate a road to which the vehicle turns right orleft.

Next, at a step ST60, display controller 6 estimates the position of thevehicle and direction thereof at a future time T1 after an elapse of apredetermined period of time from the present time. At a step ST61,display controller 6 carries out such a process as to derive the roadmap data image at the time of T1. It is noted that the level of imageprocessing at a time T1 is N1 and the image to be displayed on display 7is M1.

Display controller 6 compares road map data image M0 displayed ondisplay 7 with road map data image M1 at a future time T1 (step ST62).When the vehicle is turned at an ordinary velocity, display controller 6determines whether a position of the road map data image at which thecorresponding circumferential velocity V1 of road map data image islarger than reference value Vref (for example, Vref=50 mm/s) at a stepST63.

Consequently, if display controller 6 determines that the position ofthe road map data image at which circumferential velocity V1 is largerthan reference value Vref (No) at step ST63 is present, the routine goesto a step ST64. At step ST64, display controller 6 determines whetherimage processing level N is 0 (N=0). In this case, since N=0 (Yes at astep ST64), the routine jumps to a step ST73. At step ST73, displaycontroller 6 carries out such a process as to display image M1 at a timepoint at which the present time T has reached to the time T1. Thus,display controller 6 calculates the present position and travelingdirection of the vehicle at a step ST75. If an engine of the vehicle isturned off (No at a step ST76), then, the processing is repeated from astep ST56. That is to say, if circumferential velocity V1 on a futureroad map data image is smaller than reference value Vref, displaycontroller 7 does not carry out such a process as to variably modify thedisplay form such as the image contrast but carries out such a processas to display image M1 corresponding to a time point at which it reachesto time point T1.

On the other hand, it is predicted that the position of the road mapdata image at which circumferential velocity V1 of road map data imageis larger than reference value Vref (V1>Vref at step ST63), the routinegoes to a step ST68. At step ST68, if image processing level N hasreached to image processing level N1 at time point T1 (Yes at stepST68), the routine goes to a step ST72. At step ST72, such a process asto add display image M1 at time point T1 to image processing level N1 iscarried out.

Thereafter, when the time has reached to T1 (Yes at step ST73), displaycontroller 6 displays display image M1 on display 7 at a step ST74. At astep ST75, display controller 6 calculates the present position andtraveling direction of the vehicle. Unless the engine is turned off (Noat step ST76), the routine jumps to and returns to step ST56.

In this state, since the time has reached to T1 and the vehicle hasended to turn the intersection, No is an answer at step ST63. If No atstep ST63, the routine goes to step ST64. Since, at this time, imageprocessing level “N” is N=N1 (No at step ST64), the routine goes to astep ST65. At step ST65, image processing level is decremented by one(N=N−1). Then, at a step ST66, such an image processing as contrastadjustment is carried out. At the next step ST67, the image display iscarried out. Then, at a time point at which image processing level “N”is N=0, the road map data image at the time point T1 (newly set time T1)is displayed (step ST74). In addition, if the engine is turned off (Yesat a step ST76), the processing shown in FIGS. 23, 24, and 25 is ended.

As described above, in a case where at future time point T1, it ispredicted that the position on the road map data image at whichcorresponding circumferential velocity V1 of road map data image islarger than reference value Vref, such a process can be carried out asto relieve the troublesome feeling given to the vehicular occupant bypreviously adjusting the contrast, brightness, and focus on the road mapdata image before the time has reached to time t1. The road map dataimage displayed on display 7 can be modified in more natural sense offeeling. Consequently, the visibility of the image screen of display 7for the vehicular driver can remarkably be improved.

In vehicular display apparatus in the sixth embodiment described above,the guide route can be derived from the present position of the vehicleand from the data on the destination and winker sensor 31 and vehicularvelocity sensor 32 can be used to estimate whether the vehicle is toturn the intersection at a future time T1.

Therefore, both of timings at which the vehicle has turned in responseto the steering operation by the vehicular driver and at which the roadmap data image on display 7 can appropriately be adjusted.

FIGS. 26A, 26B, 26C, and 26D show explanatory views representingrotational timings of the vehicular turn and road map data image.

FIG. 26A shows a timing chart representing a vehicular turn and rotationtiming of rotation of road map data image.

FIGS. 26B, 26C, and 26D are timing charts representing various timingcharts representing various timing patterns when the road map data imageis rotated.

As shown in FIGS. 26A, the vehicle starts the turning at a time point oft1 and ends the turning at a time point of t2. In the example shown inFIG. 26B, the timings of the rotation start and rotation end aresynchronized with the turning of the vehicle. In addition, the imageprocessing is added to the road map data image at a time R1 immediatelybefore the start of rotation on the road map data image and the contrastadjustment and brightness adjustment are carried out. At a time R2immediately after the end of rotation, the contrast and brightness arereturned to original states.

In the example of FIG. 26C, the start timing of rotation of the road mapdata image is synchronized with the turn of the vehicle and the imageprocessing is added to the road map data image at a time R3 immediatelybefore the start of the turning (rotation) of the road map image. Inaddition, at a time point of t3 slightly immediately before the timepoint t2 which is a time point at which the turn of the vehicle isended, the rotation of the road map data image is ended. At a time R4,the road map data image under the image processing is returned to theoriginal state.

In the example of FIG. 26D, the image processing is startedsynchronizing the time point t1 at which the turn of the vehicle isstarted and, after the elapse of the time R5, the road map data image isrotated. In addition, such a process as to return the road map dataimage to the original state is carried out at the time point t2 at whichthe turn of the vehicle is ended.

Then, as shown in FIG. 26B, in a case where the timing at which thestart of turn of the vehicle is made coincident with that at which thestart of rotation of the road map data image and that at which the turnof the vehicle is ended made coincident with that at which the end ofrotation of the road map is ended, respectively, the turn of the vehicleis made coincident with the rotation of the road map data image. Thus,the unpleasant feeling that the vehicular occupant gives is reduced andit is suitable when the traveling direction of the vehicle is variedalong the path.

In addition, since, in the case of FIG. 26C, the road map data image isswitched to the display for a straight run at a time point at which theturning of the vehicle is substantially ended in such a case when thevehicle turns right or left on the traffic intersection. Hence, itbecomes possible for the vehicular driver to anticipate the subsequenttraveling direction. Consequently, the display method shown in FIG. 26Cis suitable when the vehicle turns left or right at the trafficintersection. In either the case of FIG. 26D or FIG. 26C, the displayimage on display is changed to that used for the rotation there of androad map information quantity on the display image is reduced. Hence,the vehicular driver's attention is not paid to the displayed image ondisplay 7 more than necessary. Consequently, a driving safety at thevehicular run on any traffic intersection can be improved. It is notedthat, in the case of FIG. 26D, the display of road map data image isswitched in synchronization with the actual start or end of the turn ofthe vehicle. Hence, it is unnecessary to predict the future travelingdirection of the vehicle.

The entire contents of Japanese Patent Application No. 2000-346694(filed in Japan on Nov. 14, 2000) are herein incorporated by reference.

Modifications and variations of the embodiments described above willoccur to those skilled in the art in the light of the above teachings.The scope of the invention is defined with reference to the followingclaims.

INDUSTRIAL APPLICABILITY

The present invention relates to the display apparatus and method forthe automotive vehicle such as, so-called, car navigation system andmethod, in which the road map data image which meets the vehiculardriver's drive feeling of the vehicle can be displayed and thevisibility of display can be improved. Basically, in the vehiculardisplay apparatus according to the present invention, when the road mapdata image is rotated along with the turn of the vehicle on the imagescreen of display, the display form is modified in such a manner thatthe display form on the region of the road map data image which is nearto the displayed present position of the vehicle is made different fromthat on the other region thereof which is remote from the displayedpresent position of the vehicle.

1. A display apparatus for an automotive vehicle, comprising: an imagedisplay section; a present position measuring section that measures apresent position of the vehicle; a road map storing section that storesa road map data image; a superimpose processing section thatsuperimposes a mark representing the present position of the vehicle onthe road map data image to display the road map data image on which themark is superimposed through the image display section; and displaycontrol section that rotates the road map data image displayed on animage screen of the image display section in accordance with a travelingdirection of the vehicle and varies a display form of the displayed roadmap data image between a region of the road map data image which is nearto a displayed position at which the vehicle is present and anotherregion of the road map data image which is remote from the displayedposition thereof when rotating the road map data image on the imagescreen displayed on the image display section, wherein the displayedroad map data image within the region of the road map data image whichis near to the displayed position at which the vehicle is present isclearer than the other region of the road map data image which is remotefrom the displayed position at which the vehicle is present, and thedisplay apparatus further comprises a clearness adjusting section thatadjusts the clearness of the displayed image in terms of at least one ofimage contrast, brightness, saturation, and focus.
 2. A displayapparatus for an automotive vehicle, as claimed in claim 1, furthercomprising a display form setting table storing a variationcharacteristic of the display form and wherein the display controlsection adjustably varies the display form on the image screen of theimage display section on the basis of the variation characteristicpreset in the display form setting table.
 3. A display apparatus for anautomotive vehicle, as claimed in claim 2, wherein the variationcharacteristic in the display form setting table is preset with any oneof the angular velocity, circumferential velocity, a distance from acenter of the rotation of the road map data image and a visual sensevariation rate as a parameter.
 4. A display apparatus for an automotivevehicle, as claimed in claim 1, wherein, when rotating the road map dataimage displayed on the image screen of the image display section, thedisplay control section controllably displays the road map data image onthe image screen of the image display section in such a manner thatcontents of the road map data image in the region of the road map dataimage which is near to the displayed position at which the vehicle ispresent are displayed in details and the contents thereof in the otherregion thereof which is remote from the position thereat are displayedin a simplification form.
 5. A display apparatus for an automotivevehicle, as claimed in claim 4, wherein the display control sectiondetermines whether the other region of the road map data image is to bedisplayed in the simplification form with any one of an angular velocityof the rotating road map data image, a circumferential velocity of atleast a given spot on the other region, a distance of the given spotfrom a rotation center thereof, and a visual sense variation rate as aparameter.
 6. A display apparatus for an automotive vehicle, as claimedin claim 1, wherein the display control section varies the display formin such a manner as to superimpose the road map data image after thetraveling direction of the vehicle is changed on that before thetraveling direction of the vehicle is changed when the direction of thevehicle is changed to rotate the road map data image and to varygradually a superimposition ratio of the road map data image after thetraveling direction of the vehicle is changed to the road map image databefore the road map data image is changed from 10:0 to 0:10 as the timehas passed.
 7. A display apparatus for an automotive vehicle, as claimedin claim 1, wherein the display control section varies the display formin such a manner as to synchronize a rotation of a field of view in adriving direction of the vehicle with that of the road map image datafor the road map image to be displayed on the image screen of the roadmap data image.
 8. A display apparatus for an automotive vehicle asclaimed in claim 1, wherein the display control section differentiatethe display form of the displayed road map data image between the regionof the road map data image which is near to the displayed position atwhich the vehicle is present and another region of the road map dataimage which is remote from the displayed position thereof when rotatingthe road map data image on the image screen displayed on the imagedisplay section.
 9. A display apparatus for an automotive vehicle, asclaimed in claim 1, wherein the display control section comprises avehicular traveling route direction predicting section that predicts adirection of a traveling route of the vehicle and wherein, when thedirection of the traveling route of the vehicle is varied through anangle equal to or wider than a predetermined angle, the display controlsection rotates the road map data image with the image of the vehicle asa center on the basis of a predicted data on the direction of thetraveling route of the vehicle varied through an angle equal to or widerthan the predetermined angle.
 10. A display apparatus for an automotivevehicle, as claimed in claim 9, wherein the vehicular traveling routedirection predicting section predicts the direction of the forwardingroute of the vehicle on the basis of at least one of the following data:(a) a comparison data comparing the present traveling direction of thevehicle read from the road map data image with a forward bend situationof the present traveling direction; (b) a data on a preset guide route;and (c) a data on a winker operation of the vehicle.
 11. A displayapparatus for an automotive vehicle, as claimed in claim 9, wherein thedisplay control section varies the display form of the displayed imagescreen at an earlier timing than a turning start timing of the vehicle.12. A display apparatus for an automotive vehicle, as claimed in claim9, wherein the display control section returns the display form of thedisplayed image screen on the image display section to an original stateat a time point earlier than a timing at which the vehicle has ended aturning.
 13. A display apparatus for an automotive vehicle, as claimedin claim 9, wherein the display control section varies the display formof the displayed road map data image on the image screen of the imagedisplay section after a timing at which the vehicle starts to turn andreturns the varied display form to the original state after a timing atwhich the vehicle has ended the turning.
 14. A display apparatus for anautomotive vehicle as claimed in claim 1, wherein the display controlsection further comprises: a velocity calculating section thatcalculates one of a circumferential velocity of at least one given spotof a place on the displayed image screen and an angular velocity thereofon the basis of a turning velocity of the vehicle detected by thepresent vehicle position measuring section and a display magnificationdisplayed on the image screen of the image display section; and adisplay form adjusting section that adjusts a display form of thedisplayed image screen of the image display section according to amagnitude of at least one of the circumferential velocity and theangular velocity calculated by the velocity calculating section.
 15. Adisplay apparatus for an automotive vehicle, as claimed in claim 2,wherein the display control section varies the display form in such amanner as to synchronize a rotation of a field of view in a travelingdirection of the vehicle with that of the road map image data for theroad map image to be displayed on the image screen of the road map dataimage.
 16. A display apparatus for an automotive vehicle, as claimed inclaim 14, wherein the display control section comprises a vehiculartraveling route direction predicting section that predicts a directionof a traveling route of the vehicle and wherein, when the direction ofthe traveling route of the vehicle is varied through an angle equal toor wider than a predetermined angle, the display control section rotatesand displays the road map data image with the image of the vehicle as acenter on the basis of a predicted data on the direction of thetraveling route of the vehicle varied through an angle equal to or widerthan the predetermined angle.
 17. A display apparatus for an automotivevehicle, comprising: image display means; present position measuringmeans for measuring a present position of the vehicle; road map storingmeans for storing a road map data image; superimpose processing meansfor superimposing a mark representing the present position of thevehicle on the road map image to display the road map data image onwhich the mark is superimposed through the image display section; anddisplay control means for rotating the road map data image displayed onan image screen of the image display section in accordance with atraveling direction of the vehicle and for varying a display form of thedisplayed road map data image between a region of the road map dataimage which is near to a displayed position at which the vehicle ispresent and another region of the road map data image which is remotefrom the displayed position thereof when rotating the road map dataimage on the image screen displayed on the image display section,wherein the displayed position at which the vehicle is present at whichthe vehicle is present is clearer than the other region of the road mapdata which is remote from the displayed position at which the vehicle ispresent, and the display apparatus further comprises clearness adjustingmeans for adjusting the clearness of the displayed image in terms of atleast one of image contrast, brightness, saturation, and focus.
 18. Adisplay method for an automotive vehicle, comprising: providing an imagedisplay section; measuring a present position of the vehicle; storing aroad map data image; superimposing a mark representing the presentposition of the vehicle on the road map data image to display the roadmap data image on which the mark is superimposed through the imagedisplay section; rotating the road map data image on an image screen ofthe image display section in accordance with a traveling direction ofthe vehicle while displaying the road map data image on an image screenof the image display section; varying a display form of the displayedroad map data image between a region of the road map data image which isnear to a displayed position at which the vehicle is present and anotherregion of the road map data image which is remote from the displayedposition thereof while rotating the road map data image on the imagescreen of the image display section, wherein the displayed road map dataimage within the region of the road map data image which is near to thedisplayed position at which the vehicle is present is clearer than theother region of the road map data image which is remote from thedisplayed position at which the vehicle is present; and adjusting theclearness of the displayed image in terms of at least one of imagecontrast, brightness, saturation, and focus.